Stair building tool



Aug. 8, 1933. F. F. GRAVELL ET AL STAIR BUILDING TOOL 2 Sheets-Sheet 1 Filed Oct. 26, 1929 INVENTORS F Gr ve// Grave II A TTORNEYS.

8- 8 1'935' F. F. GRAVELL ET AL 1,921,356

' STAIR BUILDING TOOL Filed Oct. 26, 2 Sheets-Sheet 2 INVENTORS FE G- rave I ATTOR EYS.

Patented Aug. 3, 1933 1,921,356 STAIR BUELDING TOOL Frank F. Gravell, Rochester, N. Y., and Edgar A. Gravell, Milford, Conn.

Application October 26,

18 Claims..

This invention is awood-working tool designed more particularly for use by carpenters, cabinet makers and the like for performing various operations' including rabbeting, dadoing and the like.

The invention has particular'utility in the build-.

ingof stairs.

Gne object of the invention is to provide a tool of the character indicated which will be simple in construction and which will enable a relatively unskilled worker to perform the more difiicult operations in woodworking such as rabbeting, dadoing and the like, with all the skill and proficiency of a skilled workman. H Another object of the invention is to provide a tool of the character indicated which maybe tom-.-

porarily secured to the work in hand and used as a teinpl t or guide for directing the saw, dado cutter, or similar wood-cutting tool of the Workman.

Another object of the invention is to provide a tool of the character indicated which may be adjusted to the various angles and dimensions of the work at hand and which, due to its adjustability, is capable of use in av multiplicity of instances arising the wood-working art. 7

These and other objects'of the invention will become apparent from the following specification read in conn ction with the accompanying drawrein wehave illustrated a preferred em- .t of our invention.

1n the drawings: .Figure 1 is a plan view of the invention.

11118 .?2 of Fig. l and showing the construction of the securing pins. i

Fig. 3 is a fragmental sectional view taken on the line two straight edges are secured.

Fig. a sectional View taken on the line 4-4 ofFig.." 1 j' Fig. 5 is a fragmental side elevation of the invention as viewed from the line 55 of Fig. 1.

:6 is a sectional. view taken on the line 6-6 of Fig. 1.

Fig. 7 is a side elevation of the invention as ved from the line 7--7 of Fig. 1. 8 is. a diagrammatic view showing the manbets in stringer of a case.

9 is a fraginental sectional view showing a portion of a stringer with the stair treads and risers fitted therein. I v

Referring more particularly to the accompanying drawings wherein like reference numerals designate like parts throughout, it will be noted 1 a fragmental sectional view taken on of 1 and showing the pivot by in which the tool is used for cutting the rab- .1929. Serial No. 402,671

that the invention comprises two straight-edge elements numbered land 2,-respectively, and an adjustable angle gauge numbered 3. The two straight edge elements 1 and 2 are generally L-shaped and are secured together with the foot 0 portions 1 and. 2 respectively, in overlying superposed relation. The members 1 and 2 are connected together for relative'adjustment by a sliding pivot comprising a bolt 18 suitably anchored on the'meinber 2 and extending through a slot '29 formed in the foot portion 1 of the member 1. The bolt 181s threaded as at 18 and is provided at the opposite extremity with an enlarged head 18 In order to accommodate the head 18 between the member 2 and the surface supporting the tool, the foot"portions 1 and 2 are preferably upset at 2, as shown in Fig. 3. The bolt 18 is further provided with a knurled nut 17 by which the members 1 and 2 may be secured in an adjusted position, and the inner contacting surfaces of the foot portions 1 and 23 of the members 1 and 2, respectively, are roughened orserrated as shown at 2 8 in order to obtain a more rigidsecurement of the members 1 and 2 when the nut 1'? is tightened. A washer 19 is interposed between the nut 1'7 and the upper surface of the foot portion 1 to prevent disturbing the members during tightening of the nut.

The angle gauge 3 isdesigned for adjustable attachment to either the straight-edge 1- or the straight-edge 2. As shown in Fig.1, the gauge 3 is secured to-the straight-edge 2 by a bolt member 16. For the purposes of adjustability the straight-edge 21s provided with an elongated slot 31 and the lower extremity of the gauge 3 is apertured, the bolt member 16 passing through the end of the'gauge and the slot in the straightedg e'2; An angle plate 4 is arrangedto overlie the gauge 3 and'the straight-edge member 2, and in order to insure a substantial and rigid joint between these members, the plate 4 carries an extension 4 which is apertured, the bolt 16 passing through said aperture in the plate, and the gauge; straight edge, and plate being adjustably secured by a nut threadedonto bolt 16, a washer 14 being -interposed between the nut 15 and the surface of the extension 4 The gauge member 3 is preferably channelshaped in cross section as shown in Fig. 4 for imparting rigidity thereto and said member is provided with a central elongated slot 33 in which IS slidingly mounted an auxiliary gauge or marker 5 arranged to'be secured in an adjusted position the straight-edge member is provided with upturned edge or flange 2. The flange is received within a groove l? formed in the plate 4 and extending transversely across the same. The groove is shown as being formed by beading or crimping the material or stock from which the plate is made, but obviously the same result may be obtained in other ways. As thus described the plate l and gauge 3 have sliding engagement with the straight-edge while the gauge also has pivotal movement with respect to both the plate and gau e. The plate 4 is preferably fashioned.

in the form of an angle gauge and to this end a circular arc concentric with the pivot bolt 16 is provided as at 32. As shown this are is in the form of an arcuate slot, one edge of which is graduated in angular degrees. A. clamping bolt carried by the gauge 3, is arranged to move in the slot 32, said bolt being threaded and provided with a nut 13 whereby the gauge may be secured to the plate in an adjusted angular position. Awasher 11 is provided on the bolt 12 between the nut and plate, in order to facilitate this operation. This construction not only provides means for measuring or for indicating the angle formed between the straight-edge member and the gauge 3 but insures a far more substantial and rigid tool, due to the fact that the plate 4 functions as a tie plate or gusset between the gauge and straight-edge.

For the purpose of securing the tool in place upon a piece of work, the straight-edge elements 1 Z are provided with a plurality of spring retracted pins 8, which, as shown in Fig. 3, are provided with head members 7, said pins and heads being mounted within cylindrical cupshaped members 6 which are secured to the mem bers 1 and 2 by suitable screws or rivets 10. The pins are retained in a retracted position by means of coiled springs 9 positioned within the cup-shaped members 6 and arranged to bear upon the heads I for the purpose of maintaining the points of the pins retracted beyond the outer surface of the straight-edges 1 and 2. The straight-edges, of course, are perforated or apertured as at 8 to permit the passage of the pins therethrough. In operation, when the tool has been adjusted to the proper position, the heads of the pins are'struck a light blow with a hammeiwwhich forces the pin intothe work piece to secure the tool in place. The friction between the pins and the work piece is normally greater than the force of the spring 9 tending-to withdraw the pins 26 so that the pins maintain the toolv in position until manually released. It is to be noted that the means provided for securing the tool to the work does not interfere in any way with making the adjustments of the plate 4, gauge 3 or gauge 5.

As shown in Fig. l, the straight-edge members 1 and 2 are provided with straight-edges 1 and 2 respectively which are arranged in opposition, facing each other and together defining an open ended slot, the lateral dimensions of which may be varied by the sliding pivot connection of the members 1 and 2. Near the pivot end of the members 1 and 2 the respective straight-edges 1 and 2 are provided with arcuate wing portions 1 and 2 which together form a curved or rounded inner end for the slot defined by the members 1 and 2. This construction enables the cutting of rabbets or dadoes designed to receive round nose stair treads.

It will be noted from an inspection of Fig. 5 that the arcuate wing portions 1d, 2d are arranged in abutting relation with respect to each other so that when the straight-edge members are adjusted toward each other, said portions 1d, 2d function as abutting shoulders to define the limit of approach of said straight-edge members with respect to each other.

An auxiliary means is provided to enable one to cut square nose rabbets or dadoes, said means comprising a bar 2'7 pivotally mounted at 26 to the straigi1t-edge 1 and arran ed to normally occupy aposition as shown in 11 lines in Fig. 1, but movable at will to a position overlying the arcuate wing portions 1 and 2 and abutting a inciting stop 20. In this position the contour of the end wall of the slot formed the straightcdges and 2 is straight so that when the tool is used as hereinafter described a square nose dado may be cut.

The tool as thus described may be made of any suitable material such as steel, brass, or the like and in order to enhance the utility of the tool as a whole, the straight-edges 1 and 2, and the edges of the slot 33 in the gauge 5 are preferably graduated in suitable units of length.

As the tool forming the subject matter of this invention. is designed more particularly for use in building stairs, the manner in which the tool may be usedfor this purpose will now be described. Referring to Fig. 8, S represents a stringer fromwhich it is desired to out one cheek of a l 4 pair of stairs. The first operation in this connection is to scribe upon the stringer S the socalled margin line M and to lay off on the string or with the line M as a base the so-cailed riser and tread lines indicated by the reference characters R and T respectively. The lines R and T are drawn without'the use of the tool being described and represent the rise and tread of a single step. The distance along the line B. from the margin line M. to the point of intersection between the lines It and T represents the rise of a given step while the length of the line T between the margin line M and the point of intersection between the lines R and T represents the width or depth of a given-tread. The lines R and T havll ing been drawn as indicated the tool is laid upon the stringer S in the manner indicated with the straight-edge 2 coinciding with theline T. Inasmuch as the rounded edge of a tread is in exv n w 1 cess of its given dimension or wldth, the straightthese treads are furnished to order togetherwith certain wedge elements which are fitted beneath th stair treads to insure a tight fit of the treads withi: cheeks of the stair case. The manner in which the treads and wedges are arranged in the finished stair case is shown in Fig. 9 wherein the treads are indicated by the reference character 50 and the wedge elements are indicated by the reference numeral 51. In adjusting the straight-edge 1 with respect to the straight-edge 2 a stair tread and a wedge element are fitted and 2 of two straight-edge elements 1 end'wise'. against the stringer and into the space between the straight-edgesl and 2 with the ex}- posed or tread surface of the tread next to and coinciding with the edge of the straight-edge element .2. The straight-edge element 1 is then adjusted untilit coincides and is in snug engagement with the wedge elementon the'bottom side thereof, the element 1 forthe purposes of this adjustment being moved angularly and bodily about the pivot bolt '18. When the element 1 has been properly adjustedin the manner described the pivot bolt 181s tightened by the knurled nut 17. 'During the adjustment just outlined the rounded edge of the stair tread *fits within the rounded end of the. slot formedby the arcuate portions 1 and 2. The straight-edge elements 1 and 2 having been thus adjusted are secured-in position upon' the stringer by driving the pins 8 into the wood as outlined hereinbefore. The gauge element 3 is now adjusted into a position in engagement with the side edge of the stringer S and secured in'such position by tightening the bolts 12 and 16. The

slide 5 is then moved to coincide with the point of intersection between the lines R and M and is secured in this position.

With the tool in this position any form of suitable cutting tool either manually operated or power operated may be worked within the slot formed between the straight-edge elements 1 and 2 using said ed es as a tool rest or guide and the stringer S thus rabbeted or dadoed to the proper depth. Where a round nosed tread is being used the rounded end of the dado is preferablymade by the use of a suitable gouge. In order to facilitate the use of power driven cutters, saws and the like in the manner just indicated, the straight-' edges .1 and 2 of the straight-edge elements 1 and 2 are preferably upset above the plane of the tool as clearly shown at 1 and 2 in Fig. 6. Fur thermore, these edges are preferably beveled away from the upper surface thereof as indicat ed at 1 and 2 in order to define a knife edge for the slot. In this manner the edges of the slot are raised above the plane of the work in order to provide a clearance for the cutting tool. This arrangement not only enables the dado or rabbet to be cut-withextreme accuracy but also prevents dulling the edge of the tool by contact with the edge of the slot. A very eifective way of cutting the rabbetsifor stair'treads is by the use of a hand operated saw with a depth gauge attachment of conventional design. w

' After the tread rabbet has been cut in the man ner indicated the tool is moved along the stringerv until the slide element 5 of the gauge 3 coincides with the point of intersection between the line T and the margin line M and the tool is secured in this position with the gauge element 3 in snug contact with the edge of the stringer. having been thus positioned is in the proper place to cut the rabbet for the succeeding stair tread and the treads are successively cut in the manner indicated. Obviously the too.- may be successively used for successive treads without readjustment and this enables a very rapid and accuratelaying cut and cutting of the stair treads with a con-' 'siderable saving of time and by'relatively un+ skilled workmen. 1

In cutting the cheek'for the opposite side of the staircase the gauge element 3 withitsassociated angle plate 4 is removed from the straigh edge element 2 and secured to the straight-edge element '1 in a similar manner. For enabling this interchange ofjthe gauge member 3 and plate 4,

The tool.

the straight-edge element 1 is provided with an elongated slot 30 and an upstanding edge flange l 'similar in all respects to the slot 31 and to flange 2 of the straight-edge element 2.

'When it is desired tocut'a stair stringerfor treads havingv a square nose in place of a round nose, the adjustable bar 27 may be swung from the position shown in Fig. 1 to a position in which a it lies transverse to, the slot formed betweenthe elements l land 2 and abutting against the stop element'ZO. 1 In this position the curved end wall of the slot is. obstructed by said: bar andthe straight edge of the bar provides the slot with a straight end wall. Forcutting treads of this type the end of the dado may be cut by a chisel in an obvious manner.

.Having thus described our invention it is ap parent that we have devised a tool which may be usednot onlylas atemplet or pattern for laying out, stair leases and rabbets of all kinds but the tool is capable also of being secured to the work to serve as a guide :elementfor guiding the'cutting tool of the workman whether the tool be a manually operated one or a'p'ower operated tool. Also, dueto the raised and beveled edges on the straight-edge elements, all possibility of dulling the tool due to injurious contact of the tool with the straight-edge elements is precluded. -It is 7 also to be noted thatbyproviding the straightedge elements 1 and 2 with a slotted pivot, these members may be moved bodily with respect to each other-as well as angularly wherebythey may be adjusted to accommodate any given tread with its associated wedge. This, is of extreme importance when itis understood that no uniform practice prevails with respect to the size or given taper tion@ The channel in the back of the gauge 5 alsoserves as a convenient housing for the heads 23 and 24 of the clamping bolts 12 and 16 respectively@ It is-further I o be noted that the surface of thetool which is placed in contact'with the work duringthe use of thetool is free from obstructions which would normallytend to interfere with the 'eilicientuse of the tool;

In conclusion it is to be understood that while we have jchosen'to describe and illustrate a preferred embodimentof our invention, such description and illustrations are but for the purpose of;

example and not to define the limits of our in-' vention which are to be determined from the scope of the appended claims.

Having'thus described ourinvention, what we claim isf,

' l. -Atool' of the c'haracterdescribed comprising astraight-edge member, an angle gauge, means pivotally and slidably connecting the gauge and straight-edge member, an angle'plate overlying the gauge and straight-edge member," said angle plate being apertured coincidentally with "the pivot point of the gauge, said gauge pivot passing through the aperture of the angle plate. and ineans associated with said pivot for securing the gauge in an adjusted position longitudinally of the straight-edge member, the angle plate having an arcuate edge concentric to thegauge pivot and at a substantial distance therefrom, and means remote from said gauge pivot associated with the gauge and plate for securing said members in adjusted angular positions of the gauge.

2. A tool of the character described comprising a straight-edge member, a'gauge pivotally and slidably mounted thereon, an angle plate overlying the gauge and provided with an upstanding open bead at one edge thereof defining a groove opening onto the underside of the plate, an upstanding edge on the straight-edge member and engaged in the groove, said groove and upstanding edge being dimensioned to, dispose the plate and straight-edge member in substantially coplanar relation, and means connecting the plate, gauge and straight-edge member together for relative adjustment the gauge being provided with a longitudinal side flange extending below the plane of the straight-edge member and angle plate. V

3. A tool of the character described comprising a pair of straight-edge members, each of said members being 7 provided with a straight-edge portion, said straight-edge members being normally disposed with the straight-edge portions thereof in opposed spaced relation, means for relatively adjusting said members laterally to conform to a desired stair tread rabbet, said means including means to secure said members in an'gularly adjusted position, a single angle gauge for defining the tread rise when operatively associated with one of said straight-edge members, and means for adjustably mounting said gauge on either of' said straight-edge members whereby the tool may be used for scribing the stair tread rabbets on either of the risers of a stair case. I

4. A tool of the character described comprising a pair of straight-edge members connected for relative adjustment by a slidable pivot, each of said straight-edge members being provided with an upstanding flange, an angle plate provided with means for operative association with the flange of either straight-edge member, an angle gauge arranged for operative association with the plate and either straight-edge, and means for securing the parts in operative position on either straight-edge member.

5. A tool of the character described comprising a pair of straight-edge members connected for relative adjustment by a slidable pivot, an angle gauge pivotally and slidingly mountable on either straight-edge member, an angle plate slidingly mountable on either straight-edge member, means 'for securing said gauge, plate, and straight-edge members in adjusted positions, and an auxiliary gauge adjustably mounted on the first mentioned gauge and movable to positions a greater or lesser distance from the pivotal center of said first mentioned gauge.

6. A tool of the character described comprising a pair of straight-edge members connected for relative adjustment by a slidable pivot, an

angle gauge movably mounted upon a straight-' edge member and adjustable towardand away from the pivot point of the straight-edge members and also angularly adjustable about its point of connection with the straight-edge member,-an auxiliary gauge mounted on the first mentioned gauge and movable to and from the point of connection of the first mentioned gauge and the straight edge member, means for securing the several parts in adjusted positions and means for interchangeably associating the gauge with either straight-edge member.

7. A tool of the character described comprising a pair of straight-edge members pivotally connected for relative adjustment, the straightedges of said members being arranged in opposed relation and upset above the general plane of the tool, said strai ht-edge members adjacent the pivotal connection being provided with arcuate wing portions forming a substantially semi-circular extremity for the slot defined by the straight-edge members.

8. A tool of the character described comprising a pair of straight-edge members pivotally connected for relative adjustment, the straightedges of said members being arranged in opposed relation and upset above the general plane of the tool, said straight-edge members adjacent the pivotal connection being provided with arouate wing portions forming a substantially semicircular extremity for the slot defined by the straight-edge members, one of said straight-edge 7 9. A tool of the character described comprising a pair of straight-edge members pivotally connected for relative adjustment, the'straight-edges of said members being arranged in opposed relation and upset above the general plane of the tool, said straight-edge members adjacent the pivotal connection being provided with arcuate wing portions forming a substantially semi-circular extremity for the slot defined by the straightedge members, and a bar movable at will to a position to overlie said arcuate wing portions whereby to define a straight end wall for the slot formed between the straight-edge members.

10. A tool of the character described comprising. a pair of straight-edge members pivotally connected for relative adjustment, the straightedges of said members being arranged in opposed relation facing one another and upset above the general plane of the tool, said straight-edge members adjacent the pivotal connection being provided with arcuate wing portions forming a substantially semi-circular extremity for the. slot defined by the straight-edge members, a bar pivotally mounted on one straight-edge member and normally occupying a position entirely within the confines thereof, said bar being movable at will to a position overlying the arcuate wing portions .of both straight-edge members, and a stop member defining said position of the bar whereby to form-a'straight end .wall for the slot between the two straight-edge members. I

11. A tool of the character described comprising a pair of straight-edgemembers, means pivotally connecting said members for relative adjustment, the pivotal connection between said members being laterally offset with respect to the straight-edge portions thereof. whereby said straight-edges are arranged in opposed spaced relation, said straight-edge members adjacent the pivotal connection being provided with complemental arcuate wing portions, forming a sub-' stantially semi-circular extremity for the slot defined by the straight-edge members.

12. 'A'tool of the character described comprising a pair of straight-edge members, means pivotally connecting said members for relative adjustment, the pivotal connection between said members being laterally oi fset with respect to the justment, the pivotal connection between said members being laterally offset with respect to the straight-edge portions thereof whereby said straight-edges are arranged in opposed spaced relation, said straight-edge members adjacent the pivotal connection being provided with complemental arcuate wing portions forming a substantially semi-circular extremity for the slot defined by the straight-edge members, and a bar mounted on one of the straight-edge members and movable at will to a position to overlie said arcuate wing portions whereby to define a straight end wall for the slot formed between the straight" edge members.

14. A tool of the character described compris ing a pair of straight-edge members, means pivotally connecting said members for relative adjustment, the pivotal connection between said members being laterally onset with respect to the straight-edge portions thereof whereby said straight edges are arranged in opposed spaced relation, said straight-edge members adjacent the pivotal connection being provided with complemental arcuate wing portions forming a sub stantially semi-circular extremity for the slot defined by the straight-edge members, and a bar mounted on one of the straight-edge members and movable at will to a position to overlie said arcuate wing portions whereby to define a straight end wall for the slot formed between the straight-edge members, one of said straight-edge members being slotted adjacent the pivotal connection whereby to permit lateral separation of said members.

15. A tool of the character described comprising a pair of straight-edge members, means pivotally connecting said members for relative adjustment, the pivotal connection between said,

members being laterally offset with respect to the straight-edge portions thereof whereby said straight-edges are arranged in opposed spaced relation and upset above the generalplane of the tool, said straight-edge members adjacent the pivotal connection being provided with complemental arcuate wing portions forming a substantially semi-circular extremity for the slot defined by the straight-edge members, a bar pivotally mounted on one straight-edge member and normally occupying a position entirely within the confines thereof, said bar being movable at will to a position overlying the arcuate wing portions of both straight-edge members, and a stop member defining said position of the bar whereby to form a straight end wall for the slot between the two straight-edge members, one of said straightedge members being slotted adjacent the pivotal connection whereby to permit lateral separation f said members. v p I 16. A tool of the character described comprising a pair of straight-edge members, a laterally extending foot portion carried by each of said. members, each of said foot portions being apertured, said straight-edge members being arranged with the straight-edge portions thereof lying in opposed relation with the foot portions in superposed relation and the apertures thereof alined, a pivot member extending through the alined apertures, and means associated with said pivot member for permitting angular adjustment ofthe straight-edge members, said straight-edge members being provided with opposed stop shoulders positioned with respect to said pivot member to define the limit of approach of said straightedge memberswith respect to eachother.

17. A tool of the character described comprising a pair of straight-edge members, a laterally extending foot portion carried by each of said members, each of said foot portions being apertured, said straight-edge members being arranged with the straight-edge portions thereof lying in opposed relation with the foot portions in superposed relation and the aperturesthereof alined. a pivot member extending through the alined apertures, means associated with said pivot member for permitting angular adjustment of the straight-edge members, and opposed stop shoulders carried by the straight-edge members adjacent the pivot members and oifset inwardly with respect to the straight-edge portions of said straight-edge members whereby to maintain said straight-edge portions of the straight-edge members spaced throughout the length thereof.

18. A tool of the character described compris ing a pair of straight-edge members, each of said members being provided with a pivot receiving aperture offset laterally, with respect to the straight-edge portion of said straight-edge members, and a pivot pin passing through said apertures, at least one of said pivot receiving apertures being elongated whereby the straight-edge members may be laterally adjusted relative to each other to conform to a given stair tread rabbet, the space between said opposed straightedge members being free'and unobstructed from end to end. i I V FRANK F. GRAVELL. EDGAR, A. GRAVELL. 

